[DarmokJalad1701]

For a really simple emulator project (not quite the level of VirtualBox), check the "IntCode" challenges from AdventOfCode 2019.

[Scipio_Afri]

I believe this is the direct link to the mentioned challenges: https://adventofcode.com/2019

[sammorrowdrums]

Those were so fun! I loved my little VM as it progressed and played pong, and commanded robots and rendered the output etc.

It's a really great fun way to learn the key concepts.